Overall, you should wear your fins with a snug, stable fit, but not so tight
that they pinch your foot anywhere. If you have room to move your toes and the fins
stay on when you try kicking them out of the water, you've achieved a good fit.

Open-heel fins should be worn with a neoprene boot for protection. If you plan
to wear a boot underneath your fins, add 1 size to your fin size to leave room.

When getting into adjustable fins, move the strap to the loosest position and insert
your entire foot in the footpocket. Then make adjustments to the strap according to fit.

For full ankle support, make sure that the fin's footpocket nearly covers edge of your
heel without engulfing it, and that its upper lip meets your instep.